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Turbo 5.3 possible tune issues Hey guys I am going to try and break this down to make it easier to understand. The vehicle. 2001 Silverado p01 ecu 3 bar ls1 style map from efisource Gen iv intake with 92mm the 4l80 (separate controller) on3 7875 turbo with fmic The issue. I tuned this using hptuners and so far I am running 10psi according to my boost gauge. AFR looks like it's supposed to. It ran good for the first 9-10 pulls I made at the dig spot, drove it home smoothly no issues. The next weekend when I did the pull it felt a little weak in higher boost range. And when I let out it misfires hard until I free rev in neutral then it's fine unless I try and boost again. What I've tried New wires/plugs Vcm logs look okay. coils are all firing at idle What I'm questioning. At 10psi it reads 135kpa At idle it reads 70kpa Does that seem correct? Or do I have a bad out of the box map sensor. Linear and offset where provided by efisource. Any suggestions? Tia |
Originally Posted by bbowerman
(Post 19897706)
Hey guys I am going to try and break this down to make it easier to understand. The vehicle. 2001 Silverado p01 ecu 3 bar ls1 style map from efisource Gen iv intake with 92mm the 4l80 (separate controller) on3 7875 turbo with fmic The issue. I tuned this using hptuners and so far I am running 10psi according to my boost gauge. AFR looks like it's supposed to. It ran good for the first 9-10 pulls I made at the dig spot, drove it home smoothly no issues. The next weekend when I did the pull it felt a little weak in higher boost range. And when I let out it misfires hard until I free rev in neutral then it's fine unless I try and boost again. What I've tried New wires/plugs Vcm logs look okay. coils are all firing at idle What I'm questioning. At 10psi it reads 135kpa At idle it reads 70kpa Does that seem correct? Or do I have a bad out of the box map sensor. Linear and offset where provided by efisource. Any suggestions? Tia |
That's what I was thinking. The cam is a .585/.585 cam. The numbers didn't add up to me. 35kpa doesn't equal 10 psi but my gauge reads 10 psi. The fueling is fine but I may have it scaled around that issue. And if I don't hit boost this truck is really smooth. I can upload a log and the tune file when I get home if that would help. |
I would look to see if you're hitting some kind of cut out or something. Posting a log/tune would help. |
2 Attachment(s) I attached a log and a tune. This tune RAF was off but I have since redone it. Everything else is almost identical. |
For 1 your high and low octane tables don't match, 2 your shift tables for the trans are all wack. PE tps is way too high and you have PE delay on 2k as well. Spark seems to be really low in your cruising area as well. |
High and low octane maps are the same now. that was the last tune I had although my new one is almost the same. And trans tables are null it has an aftermarket controller that does that. |
70kPa at Idle? So youre boosting at idle? If you meant -70kPa you have a vacuum leak. If you truly meant 70kPa, your MAP sensor is probably fucked, or the calibration for it is fucked. If youre MAP says youre boosting 130 and your boost gauge says 10psi, youre probably dumping too much fuel, which explains the power loss and backfiring. |
Yea man it's odd it says 70kpa at idle has ever since the new map sensor with vendor supplied values. Has me scratching my head. I have a good 2 bar map I may try just to see what it shows. |
Originally Posted by bbowerman
(Post 19897778)
Yea man it's odd it says 70kpa at idle has ever since the new map sensor with vendor supplied values. Has me scratching my head. I have a good 2 bar map I may try just to see what it shows. |
Originally Posted by Fuhnortoner
(Post 19897779)
You probably need to change the calibration within the PCM for the 3 bar. Sorry I'm fairly new at this and learning as I go. |
Originally Posted by bbowerman
(Post 19897780)
Linear and offset? They are from the supplier. Sorry I'm fairly new at this and learning as I go. |
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Originally Posted by Fuhnortoner
(Post 19897787)
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I did see them talking of a maf pid I could have missed. May look into that when I'm off work. |
MAF is set to fail at 0hz so it's SD tune only. I assembly this bypasses your rpm threshold for airflow cause above 2400rpms it's set to read MAF only. None of the other spark or trans comments explain why it's fine at cruise and misfires at WOT. And 70kpa is vacuum, not boost. 100kpa is normally NA WOT. You could have a bum sensor or and offset and linearity issue as stated. |
Originally Posted by ddnspider
(Post 19897827)
MAF is set to fail at 0hz so it's SD tune only. I assembly this bypasses your rpm threshold for airflow cause above 2400rpms it's set to read MAF only. None of the other spark or trans comments explain why it's fine at cruise and misfires at WOT. And 70kpa is vacuum, not boost. 100kpa is normally NA WOT. You could have a bum sensor or and offset and linearity issue as stated. https://cimg7.ibsrv.net/gimg/ls1tech...aaa970b620.png |
Atmospheric is also known as 15 PSI. |
Originally Posted by G Atsma
(Post 19897851)
Atmospheric is also known as 15 PSI. |
Sorry. I forgot to say at sea level. My bad... |
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